Device for feeding logs through a processing machine

ABSTRACT

An apparatus for feeding logs, blocks or similar elongate objects through one or several successive saws or other processing machines in a wood-processing mill includes a pair of vertically extending log-holding arms supported by and movable along an overhead trackway extending parallel to the desired feeding line for the logs. The log-holding arms have a loggrasping means at their lower ends adapted to grasp and hold the opposite ends of the log while moving the log along the feeding line. Each log-grasping means comprises a clamping device which clamps an end of the log from above and below. The clamping device includes a lower, horizontally projecting clamping member fixed to its arm and upon which a lower circumferential undersurface portion of the log end rests. The device further includes an upper clamping member moved along the arm by a cylinder into clamping engagement with an upper circumferential surface portion of the end of the log, thereby clamping the log end from above and below securely between the upper and lower clamping members.

Waite States Patent 1 Ackerfeldt 1 Sept. 4, 1973 1 DEVICE FOR FEEDINGLOGS THROUGH A PROCESSING MACHINE [75] inventor: Bo Ingemar Ackerleldt,Ascona,

Switzerland [73] Assignee: U.S. Natural Resources, Inc.,

Portland, Oreg.

[22] Filed: Oct. 4, 1971 [21] Appl. No.: 186,309

[30] Foreign Application Priority Data Oct. 9, 1970 Sweden 7013717 [52]US. Cl 143/125, 143/117, 143/25 [51] Int. Cl 1327b 29/08 [58] Field ofSearch 143/125 R, 125 A,

143/25, 117, 105, 126 P, 126 A, 127, 128, 129, 130, 131, 54 A; 83/409[56] References Cited UNITED STATES PATENTS 3,503,428 3/1970 Ackerfeldt143/117 Primary ExaminerDonald R. Schran Attorney-Stephen W. Blore eta1.

[5 7 ABSTRACT An apparatus for feeding logs, blocks or similar elongateobjects through one or several successive saws or other processingmachines in a wood-processing mill includes a pair of verticallyextending log-holding arms supported by and movable along an overheadtrackway extending parallel to the desired feeding line for the logs.The log-holding arms have a log-grasping means at their lower endsadapted to grasp and hold the opposite ends of the log while moving thelog along the feeding line. Each log-grasping means comprises a clampingdevice which clamps an end of the log from above and below. The clampingdevice includes a lower, horizontally projecting clamping member fixedto its arm and upon which a lower circumferential undersurface portionof the log end rests. The device further includes an upper clampingmember moved along the arm by a cylinder into clamping engagement withan upper circumferential surface portion of the end of the log, therebyclamping the log end from above and below securely between the upper andlower clamping members.

13 Claims, 5 Drawing Figures PATENTEDSEP 1975 DEVICE FOR FEEDING LOGSTHROUGH A PROCESSING MACHINE BACKGROUND OF THE INVENTION 1. Field of theInvention The present invention is related to a device for feeding logs,cants, blocks or similar elongate objects through one or severalsuccessive saws or other processing machines. The device according tothe invention is of the general type known in the prior art, whichcomprises substantially vertical logholding arms, which are supported byand movable along a trackway extending above the saw parallel to thedesired feeding line for the logs and which are adapted to grasp andhold the end of a log at their lowermost ends while feeding the logalong said feeding line. Generally each log is supported between twosuch logholding arms, which hold the log at its fore and rear endsrespectively. Prior art feeding devices of this type are described, forinstance, in the Swedish Pat. Nos. 301,868 and 306,162.

2. Description of the Prior Art A problem in'feeding devices of thistype is to provide such a design of the lowermost ends of the logholdingarms that they obtain a sufficiently firm grip of the ends of the logsto prevent any displacement of the log, in particular rotation of thelog about its longitudinal axis, during the feeding and in particularthe sawing or other processing of the log. This problem is made moredifficult in that the log-holding arms must in most cases be able topass together with the log between two processing tools, for instance,two saw blades, disposed side by side, wherefore the lateral extensionof the logholding arm must be kept small at least at the lowermost endof the log-holding arm, where this cooperates with the end of the log.

Previously one has solved this problem by providing the lowermost end ofthe log-holding arms with a number of horizontally projecting spikesadapted to be pressed into the end surface of the log, whereby the logwill be supported and kept in a fixed position by the log-holding arm.However, this solution is not entirely satisfactory. Thus, a reliablegrip between the logholding arm and the end of the log requiresobviously that the end surface of the log be substantially plane andperpendicular to the longitudinal axis of the log so that all spikes onthe log-holding arm can be pressed into the end surface of the log.However, very often the end surface of the log is such that only thosespikes closest to the center of the end surface will project into theend surface, giving a very unreliable grip, as these spikes areincapable of preventing rotation of the log about its longitudinal axis.Such a rotation of the log must, however, be prevented if accurateprocessing of the log, for instance sawing, is to be achieved. Further,a considerable axial force between the log-holding arm and the log isrequired if the spikes on the log-holding arm are to be pressed into theend surface of the log and kept in this position.

Therefore, with such prior devices it is necessary that the log beclamped firmly between two log-holding arms acting against the fore endsurface and the rear end surface of the log respectively. It is notpossible to hold the log, for example, only at its rear end with asingle log-holding arm, while the fore end of the log is permitted toslide on a stationary support member that may be provided with guidegrooves or similar arrangement for the guiding of the fore end of thelog. Yet such a single-arm arrangement might otherwise be suitable atsmaller sawmills adapted for a comparatively limited production.

Further, with such prior devices the necessary axial clamping forcebetween the log and the log-holding arms must obviously be taken up bythe log-holding arms and the coupling means between the log-holding armsand their drive means. Therefore these components and members of theprior devices must be heavily dimensioned in order to withstand theseforces without undue strain.

SUMMARY OF THE INVENTION A primary object of the present invention istherefore to provide a feeding device of the general type mentioned inthe foregoing, at which the above-discussed problems are solved in asatisfactory way. According to the invention this is achieved in afeeding device designed in accordance with the accompanying claims.

In a device according to the invention, a reliable grip between thelog-holding arm and the end of the log, preventing any displacement orrotation of the log relatively to the log-holding arm, is achievedindependent of the shape of the end surface of the log.

Further, in a device according to the invention, no or only a very smallaxial force is required between the log-holding arm and the log in orderto achieve a reli able grip of the end of the log. Therefore, theinvention can also be used in a feeding device, in which the log isgripped at one end only by only one log-holding arm. The single armpreferably grips the rear end of the log, whereas the opposite end ofthe log may rest upon and slide along a stationary support surface.

Further, in a device according to the invention, it is not necessarythat the log-holding arm and associated members be dimensioned for anylarge axial clamping forces between the log-holding arm and the log.

BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will befurther described with reference to the accompanying drawing, whichillustrates by way of example an embodiment of a log-feeding deviceaccording to the invention. In the drawings:

FIG. 1 is a partial side view of a sawmill provided with a log-feedingdevice according to the invention;

FIG. 2 is a section through the sawmill in FIG. 1 taken along the lineII-II in FIG. 1;

FIG. 3 is a side view on an enlarged scale of the lower portion of alog-holding arm;

FIG. 4 is a front view of the log-holding arm in FIG. 3 as seen from theline IV- -IV in FIG. 3; and

FIG. 5 is a section through the log-holding arm in FIG. 3 taken alongthe line V-V in FIG. 3.

The drawings show schematically a sawmill comprising a double band sawwith two saw blades 1 and 2. The feeding direction for thelogs throughthe saw is indicated with an arrow 3 in FIG. 1. The logs are fed throughthe saw by means of a feeding device, which to a large extent isdesigned in the same manner as the feeding device shown in FIGS. 1 to 4in the Swedish Pat. No. 301,868 and which is described in detail in saidpatent.

Thus, the feeding device comprises a fore log-holding arm 4 and a rearlog-holding'arm 5, which are mounted on two separate carriages 6 and 7respectively. The carriages are supported by and movable along anoverhead trackway 8 extending above the saw parallel to the desiredfeeding line or path for the logs through the saw from the input side tothe output side of the saw. The log-holding arms 4 and 5 are pivoted intheir associated carriages and can be moved by means of hydrauliccylinders 9 and 10 respectively or similar actuating means between avertical active position and a substantially horizontal inactive orreturn position. For driving the carriages 6 and 7 with the log-holdingarms 4 and 5 an endless drive chain 11 is provided, which can be drivenselectively in the one or the opposite direction. By the aid of suitablecoupling means the carriages 6 and 7 for the log-holding arms 4 and 5can be selectively connected to and disconnected from this drive chain 11, as described more in detail in the Swedish Pat. No. 301 ,868. For thecarriage 6 of the fore log-holding arm 4 a spring-biased retainer pawl12 with an associated release cam 13 is mounted on the trackway 8 at theinput side of the saw in the manner described more in detail in theSwedish Pat. No. 30l,868.

In order to increase the production capacity the feeding deviceillustrated by way of example in the drawings is provided with anadditional pair of log-holding arms designed in exactly the same manneras the log-holding arms 4 and 5 with their associated carriages 6 and 7.Of this additional pair of log-holding arms, however, only the rearlog-holding arm 14 with its associate carriage 15 is shown in FIG. 1. Ascan be seen from FIG. 2, the trackway 8 for the carriages 6 and 7 of thelog-holding arms 4 and 5 is disposed somewhat to the one side of thevertical plane containing the feeding line for the logs, whereas thetrackway 16 for the carriage 15 of the additional rear log-holding arm14 and for the carriage of the corresponding fore log-holding arm, notshown in the drawing, is disposed on the opposite side of said verticalplane. However, all log-holding arms are bent in such a way that theyhave their lowermost portions disposed in the vertical plane containingthe feeding line for the logs. As can be seen in FIG. 2, this makes itpossible for a carriage having its log-holding arm raised in thehorizontal inactive or return position and a carriage having itslog-holding arm lowered in the vertical active position to pass eachother when moving in opposite directions. The carriage 15 of the rearlogholding arm 14 and the carriage of the associated fore log-holdingarm, not shown in the drawing, are driven either by means of a separatedrive chain, corresponding to the drive chain 11, or by the same drivechain 11 as the carriages 6 and 7 for the log-holding arms 4 and 5respectively. The pairs are driven in such a manner that when one pairof log-holding arms is moved in the feeding direction 3, the other pairis moved in the opposite return direction and vice versa. In this waythe one pair of log-holding arms can feed a log through the saw at thesame time as the second pair of log-holding arms is returned from theoutput side to the input side of the saw.

For holding the logs while feeding them though the saw, the lower endportions of the log-holding arms are of a special design incorporating alog end-clamping mechanism, as shown more in detail in FIGS. 3, 4 and 5for the rear log-holding arm 5. At its lowermost end this clampingmechanism for log-holding arm 5 includes a lower clamping means in theform of a ledge of platform 17, which is rigidly attached to thelogholding arm and which projects substantially horizontally therefromin the feeding direction of the logs, The log-holding arm isadditionally provided with an upper clamping means including a slide orrunner 18, which is movable in vertical direction relative to thelogholding arm 5 and lower clamping means, and is guided in a slot inthe arm, as most readily seen in FIG. 5. This slide 18 is provided witha clamping arm 20, which projects in the feeding direction of the logs.The outer end of this clamping arm curves downwardly, as shown in FIG.3.

The log-holding arm 5 carries also a clamp-inoving means comprisinghydraulic or pneumatic cylinder 21 or a similar force-generatingactuating means, which is coupled to slide 18. By this hydrauliccylinder 21, slide 18 and thus clamping arm 20 of the upper clampingmeans can be forced downwardly toward platform 17 of the lower clampingmeans. If, as illustrated in FIG. 3, the rear end of a log 22 ispositioned in front of logholding arm 5, the arm 20 may by the hydrauliccylinder 21 be pressed downwards against the upper circumferentialsurface of the log 22 adjacent the rear end of the log, whereby the endof the log is pressed downwards against platform 17. Thus, the end ofthe log 22 is clamped between the arm 20 of the upper clamping means andthe platform 17 of the lower clamping means.

In order to produce a better grip, the clamping arm 20 may be providedwith downwardly pointing spikes 20a and the platform 17 may be providedwith upwardly pointing spikes 17a. These are forced into thecircumferential surface of the log 22 from above and below respectively,when the end of the log is clamped between clamping arm 20 and platfonn17.

Instead of such spikes the platform 17 may, for instance, be providedwith projecting sharp edges extending in the feeding direction.Similarly clamping arm 20 may be provided with similar downwardly facingsharp edges, also extending in the feeding direction. Such edges willeffectively resist rotation of the log 22 about its longitudinal axis.

In the same manner the fore log-holding arm 4 is provided with a lowerclamping means including platform 23 projecting backwards from the armand an upper clamping means including clamping arm 24 also projectingbackwards. A hydraulic cylinder 25 connected to arm 4 moves clamping arm24.

The carriages for the log-holding arms are guided laterally by means ofguide rails 26 and 27 respectively, as shown in FIGS. 1 and 2. In theirlowered vertical active position the lowermost ends of the log-holdingarms are additionally guided laterally in a groove 28 provided in aguide rail 29 extending below the feeding line.

For receiving a log'22 to be fed through the saw, a number offork-shaped support members 30, 31 and 32 are provided at the input sideof the saw. These support members can be pivoted between an upper and alower position. Two or several suitably positioned such support memberscan be raised to their upper position for receiving and supporting a log22 which has been supplied to the input side of the saw in any suitablemanner, not illustrated in the drawing. A log 22 resting in these raisedsupport members, for instance 30 and 32 in FIG. 1, can be rotated aboutits longitudinal axis to a position suitable for the sawing of the logby means of rotating means 33, which in the illustrated embodiment ofthe invention consists of two endless chains dis- OPERATION When the log22 supported in the raised support members 30 and 32 has been rotatedin'this manner to a desired position, the rear log-holding arm 5, whichis in its vertical active position, is started by the drive chain 11 andso moves toward the rear end surface of the log 22, whereby the log isput into motion. As soon as the log 22 starts to move, the hydrauliccylinder 21 is activated in a suitable automatic way. forcing clampingarm downwardly against the upper circumferential surface of the log 22.

The carriage 6 of the fore log-holding arm 4 is disconnected from thedrive chain 11 and thus is initially stationary and retained by thespring-biased pawl 12.

As the log 22 moves forward, however, the fore end surface of the logstrikes the fore log-holding arm 4, whereby arm 4 moves forward togetherwith its carriage 6 against the action of the spring-biased pawl 12. Assoon as the fore log-holding arm 4 starts to move, the hydrauliccylinder is activated in any suitable automatic manner to forceclampingarrn 24 downwardly against the upper surface of log 22 at thefore end of the log. During this process, support forks and 32supporting the log 22 lower, whereby log 22 descends. The clamping arms20 and 24 follow the log in its downward motion while maintaining adownwardly directed force upon the log.-

When the ends of the log 22 reach the projecting fixed platforms l7 and23 of the lower clamping means on the log-holding arms 5 and 4respectively, the downward motion of log 22 ceases. Thus the rear end ofthe log'becomes clamped securely between platform 17 and the clampingarm 20 of the clamping mechanism on the rearlog-holding arm 5 by theforce exerted by hydraulic cylinder 21. At the same time, the fore endof the log becomes clamped in the same manner between the platform 23and the clamping arm 24 of the clamping mechanism on the forelog-holding arm 4 by the force exerted by the hydraulic cylinder 25. Inthis way the log 22 is held at both ends from above and below in a veryfirm grip, which effectively prevents any rotation of the log '22 aboutits longitudinal axis.

.When during the continued movement of the fore log-holding arm 4 in thefeeding direction the retainer pawl 12 is released by the release cam13, carriage 6 of the fore log-holding arm 4 is automatically connectedto drive chain 11 in the manner described in Swedish Pat. No.- 301,868.As, obviously, no substantial axial clamping force is necessary betweenthe log-holding arms 4 and 5 and the log 22 in order to hold the log 22firmly in the log-holding arms, the biasing spring for the retainer pawl12 may be comparatively weak. This reduces substantially the strainexerted upon log-holding arms 4 and 5 and their associated carriages 6and 7, and

' in particular upon the coupling means between these carriages and thedrive chain 1 1. Also the tension in the drive chain will be reducedcorrespondingly. Therefore all these components can be dimensioned forsmall strains, which reduces the weight and costs of these componentsand also the wear on them.

It should be noted that the invention is not restricted to theembodiment thereof illustrated in the drawings and described in theforegoing. Thus, the invention is applicable with the same advantagesalso in other types of log-feeding devices provided with verticallogholding arms adapted to hold only one end of a log while feeding thelog through one or several processing machines. Thus, the invention may,for instance, be used with great advantage in a feeding device, in whichthe log is held only by one log-holding arm at its one end, preferablyat its rear end, while the opposite end of the log slides along astationary support surface. Such surface may be provided with guidegrooves or guide edges extending in the feeding direction.

Having illustrated and described what is now a preferred embodiment ofmy invention and possible alternative embodiments, it should now beapparent that the invention permits of modification in arrangement anddetail. I claim as my invention all such modifications as come withinthe true spirit and scope of the following claims.

I claim:

1. A device for feeding a log or a similar elongated object through asaw or similar wood-processing machine comprising:

at least one generally vertically extending log-holding arm means, anoverhead trackway means extending above and parallel to the desiredfeeding path of the logs supporting said arm means for movementtherealong,

said log-holding arm including at a lower portion thereof a log endclamping mechanism adapted to grasp and hold an end portion of a log,

said mechanism including a lower clamping means for supporting acircumferential undersurface portion of said, log and an upper clampingmeans spaced above said lower clamping means for clampingly engaging anupper circumferential surface portion of said log,

means mounting at least one of said upper and lower clamping means onsaid arm for movement in a vertical direction relative to the other saidclampmg means,

and means operably connected to the movable one of said clamping meansfor moving said vmovable clamping means into clamping engagement with acircumferential surface portion of said log and for maintaining aclamping force between said upper and lower clamping means and said log.

2. A device according to claim 1 wherein one of said upper andlowerclamping means is fixed to said logholding arm and the other of saidupper and lower clamping means is movablevertically along saidlogholding arm.

3. A device according to claim ll wherein said lower clamping'means isfixed to said log-holding arm and said upper clamping means is movablevertically along .said log-holding arm.

ing one of said upper and lower clamping means comprising aforce-generating means connected to said clamping arm for forcing itdownwardly against an upper circumferential surface portion of the logat the end thereof, whereby the end of the log is clamped between saidclamping arm and said support platform.

6. A device according to claim wherein said support platform is rigidlyattached to said log-holding arm.

7. A device according to claim 5 wherein said support surface of saidsupport platform is provided with one or several upwards pointing spikesadapted to penetrate the circumferential surface of the log.

8. A device according to claim 5 wherein said support surface of saidsupport platform is provided with one or several projecting sharp edgesextending substantially in the direction of the feeding line and adaptedto penetrate the circumferential surface of the log.

9. A device according to claim 5 wherein said clamping arm is providedwith one or several downwards pointing spikes adapted to penetrate thecircumferential surface of the log.

10. A device according to claim 5 wherein said clamping arm is providedwith one or several projecting sharp edges extending substantially inthe direction of the feeding line and adapted to penetrate thecircumferential surface of the log.

11. A device according to claim 5 wherein said clamping arm is mountedon a slide movable in a guide path in the log-holding arm.

12. A device according to claim 1 wherein the means for moving one orthe other of said upper and lower clamping means includes afluid-powered extensible cylinder means carried by said log-holding arm.

13. A device according to claim 1 wherein there are a pair of saidlog-holding arms, one for each of the opposite ends of a log or similarelongated object, each provided with one of said clamping mechanisms.

1. A device for feeding a log or a similar elongated object through asaw or similar wood-processing machine comprising: at least onegenerally vertically extending log-holding arm means, an overheadtrackway means extending above and parallel to the desired feeding pathof the logs supporting said arm means for movement therealong, saidlog-holding arm including at a lower portion thereof a log end clampingmechanism adapted to grasp and hold an end portion of a log, saidmechanism including a lower clamping means for supporting acircumferential undersurface portion of said log and an upper clampingmeans spaced above said lower clamping means for clampingly engaging anupper circumferential surface portion of said log, means mounting atleast one of said upper and lower clamping means on said arm formovement in a vertical direction relative to the other said clampingmeans, and means operably connected to the movable one of said clampingmeans for moving said movable clamping means into clamping engagementwith a circumferential surface portion of said log and for maintaining aclamping force between said upper and lower clamping means and said log.2. A device according to claim 1 wherein one of said upper and lowerclamping means is fixed to said log-holding arm and the other of saidupper and lower clamping means is movable vertically along saidlog-holding arm.
 3. A device according to claim 1 wherein said lowerclamping means is fixed to said log-holding arm and said upper clampingmeans is movable vertically along said log-holding arm.
 4. A deviceaccording to claim 1 wherein said lower clamping means comprises asupport platform projecting substantially horizontally in the directionof the feeding path towards the log and having a support surface for theend of the log.
 5. A device according to claim 4 wherein said upperclamping means comprises a clamping arm above said support platformprojecting substantially in the same direction as said support platform,said means for moving one of said upper and lower clamping meanscomprising a force-generating means connected to said clamping arm forforcing it downwardly against an upper circumferential surface portionof the log at the end thereof, whereby the end of the log is clampedbetween said clamping arm and said support platform.
 6. A deviceaccording to claim 5 wherein said support platform is rigidly attachedto said log-holding arm.
 7. A device according to claim 5 wherein saidsupport surface of said support platform is provided with one or severalupwards pointing spikes adapted to penetrate the circumferential surfaceof the log.
 8. A device according to claim 5 wherein said supportsurface of said support platform is provided with one or severalprojecting sharp edges extending substantially in the direction of thefeeding line and adapted to penetrate the circumferential surface of thelog.
 9. A device according to claim 5 wherein said clamping arm isprovided with one or several downwards pointing spikes adapted topenetrate the circumferential surface of the log.
 10. A device accordingto claim 5 wherein said clamping arm is provided with one or severalprojecting sharp edges extending substantially in the direction of thefeeding line and adapted to penetrate the circumferential surface of thelog.
 11. A device according to claim 5 wherein said clamping arm ismounted on a slide movable in a guide path in the log-holding arm.
 12. Adevice according to claim 1 wherein the means for moving one or theother of said upper and lower clamping means includes a fluid-poweredextensible cylinder means carried by said log-holding arm.
 13. A deviceaccording to claim 1 wherein there are a pair of said log-holding arms,one for each of the opposite ends of a log or similar elongated object,each provided with one of said clamping mechanisms.